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Sirolimus is recognized as a P-glycoprotein (P-gp) substrate with poor water-solubility. To improve its solubility and bioabsorption, self-microemulsifying drug delivery systems (SMEDDS) containing a novel P-gp inhibitor, honokiol, were prepared. The aim of this work was to evaluate the enhanced transport of sirolimus SMEDDS as well as the roles of honokiol. In situ single-pass intestinal perfusion and in vitro human colon adenocarcinoma (Caco-2) cell models were applied to study the effects of honokiol within SMEDDS on the transport of sirolimus. The results indicated that a combination of honokiol with sirolimus in SMEDDS did not significantly alter the particle size, polydispersity index and release of drugs. In addition, the absorption rate constant (Ka) as well as the effective permeability coefficients (Peff) of sirolimus in situ intestinal absorption, and the apparent permeability coefficients (Papp) of sirolimus in caco-2 cells were significantly enhanced by cremophor EL-based SMEDDS with honokiol as compared with those of SMEDDS without honokiol. Rhodamine123 uptake rate in caco-2 cells and in vitro cytotoxicity of sirolimus were enhanced by honokiol in SMEDDS indicating a substantial P-gp inhibition of honokiol. In conclusion, coadministration of honokiol with poor soluble P-gp substrate in SMEDDS, could serve as a favorable approach for oral delivery.

The aim of this study was to prepare wheat germ agglutinin (WGA)-modified liposomes encapsulating clarithromycin and to evaluate their in vitro and in vivo efficacy against Methicillin-resistant Staphylococcus aureus (MRSA). Physicochemical parameters, minimum inhibitory concentrations, in vitro killing kinetic, cellular uptake, biofilm formation inhibition and pre-formed biofilm destruction, biodistribution, in vivo antibacterial efficacy against MRSA, and phagocytosis into macrophages for liposomes loading clarithromycin were determined. The minimum inhibitory concentration and the time–kill curve for WGA-modified liposomal clarithromycin were better than those of free and nonmodified liposomal clarithromycin. Flow cytometry analysis displayed that liposomes could deliver more Coumarin 6, a fluorescent probe, into bacteria because of the conjugation of WGA. Besides, WGA-modified liposomal clarithromycin inhibited formation of S. aureus (ATCC 29213) and MRSA biofiom, and prompted the biofilm disassembly at lower concentrations below MIC. Effective accumulation of liposomes was displayed in the enterocoelia of the mice because of WGA. The number of MRSA colony-forming units in the kidney and spleen in mice treated with WGA-modified liposomal clarithromycin was significantly lower than that treated with free and nonmodified clarithromycin (p

Objectives The aims of the present study were to design polymeric micelles loading sirolimus with honokiol to increase drug solubility and to gain an insight into the effect of honokiol on oral transport of P-glycoprotein substrate (P-gp). Methods Particle size distribution, encapsulation efficiency, drug-loading content and in-vitro release of sirolimus-loaded micelles with honokiol were determined. Transport of sirolimus-loaded micelles across Caco-2 cell monolayers and jejunum segment of rats were investigated. In-vitro cytotoxicity experiments and the cellular uptake study were carried out via sulforhodamine B assay and flow cytometry, respectively. Key findings A coadministration of honokiol with sirolimus in micelles did not significantly modify the particle size, polydispersity index and release of drugs demonstrating successful loading within the micelles. The apparent transport coefficients (Papp) and effective permeability (Peff) of sirolimus were increased with more amount of honokiol loaded in micelles. Cellular uptake study demonstrated that rhodamine123 uptake rate was enhanced by honokiol-loaded micelles, indicating substantial P-gp inhibition action by honokiol and mPEG-PLA-based micelles. Conclusion Oral transport of sirolimus was significantly improved by coadministration with honokiol, an inhibitor of the P-gp, in polymeric micelles formulation.